Atomic reactor

Carbon dioxide is used in the manufacture of sodium carbonate by the ammonia-soda process, urea, salicyclic acid (for aspirin), fire extinguishers and aerated water. Lesser amounts are used to transfer heat generated by an atomic reactor to water and so produce steam and electric power, whilst solid carbon dioxide is used as a refrigerant, a mixture of solid carbon dioxide and alcohol providing a good low-temperature bath (195 K) in which reactions can be carried out in the laboratory. 

The increasing number of atomic reactors used for power generation has been questioned from several environmental points of view. A modern atomic plant, as shown in Fig. 28-3, appears to be relatively pollution free compared to the more familiar fossil fuel-fired plant, which emits carbon monoxide and carbon dioxide, oxides of nitrogen and sulfur, hydrocarbons, and fly ash. However, waste and spent-fuel disposal problems may offset the apparent advantages. These problems (along with steam generator leaks) caused the plant shown in Fig. 28-3 to close permanently in 199T. 

In contact with molten salts, the nickel-base alloys behave much more satisfactorily than is the general experience with molten metals. For this reason they are considered as structural materials in atomic reactors using fluoride mixtures as coolants and are used as vessels for heat-treatment salt baths, as thermocouple sheaths and in similar applications. 

Zirconium Zirconium was originally developed as a construction material for atomic reactors. Reactor-grade zirconium contains very... 

Preparation of a Typical Au-Acetone Colloid. The metal atom reactor has been described previously. (39,59, 60) As a typical example, a W-A1 0 crucible was charged with 0.5Qg Au metal (one piece). Acetone (300 mL, dried over K2C0 ) was placed in a ligand inlet tube and freeze-pump-thaw degassed with several cycles. The reactor was pumped down to 1 x 10 Torr while the crucible was warmed to red heat. A liquid N2 filled Dewar was placed around the vessel and Au (0.2g) and acetone (80g) were codeposited over a 1.0 hr period. The matrix was a dark purple color at the end of the deposition. The matrix was allowed to warm slowly under vacuum by removal of the liquid N2 from the Dewar and placing the cold Dewar around the reactor. 

The most widely used radio-isotope, iodine-131, is prepared in this way (S3), (55), (59), (69), (96). It is produced in the atomic reactor by bombardment of tellurium, one of the isotopes of which decays by -emission to iodine 131 ... 

Polonium is found only in trace amounts in the Earths crust. In nature it is found in pitchblende (uranium ore) as a decay product of uranium. Because it is so scarce, it is usually artificially produced by bombarding bismuth-209 with neutrons in a nuclear (atomic) reactor, resulting in bismuth-210, which has a half-hfe of five days. Bi-210 subsequently decays into Po-210 through beta decay The reaction for this process is Bi( ) Bi — °Po + (3-. Only small commercial milligram amounts are produced by this procedure. 

Astatine is located just below iodine, which suggests that it should have some of the same chemical properties as iodine, even though it also acts more hke a metal or semimetal than does iodine. It is a fairly heavy element with an odd atomic number, which assisted chemists in learning more about this extremely rare element. The 41 isotopes are man-made in atomic reactors, and most exist for fractions of a second. The elements melting point is about 302°C, its boiling point is approximately 337°C, and its density is about 7g/cm. ... 

Gadohnium is the 40th most abundant element on Earth and the sixth most abundant of the rare-earths found in the Earths crust (6.4 ppm). Like many other rare-earths, gadolinium is found in monazite river sand in India and Brazil and the beach sand of Florida as well as in bastnasite ores in southern California. Similar to other rare-earths, gadolinium is recovered from its minerals by the ion-exchange process. It is also produced by nuclear fission in atomic reactors designed to produce electricity. 

Haley Tf et al Toxicological studies on polyphenyl compounds used in atomic reactor moderator-coolants. Toxicol Appl Pharmacol 1 515-523, 1959... 

Uses. Structural material for atomic reactors ingredient of priming and explosive mixtures reducing agents pigment textile water repellent... 

Fig. 3. Metal atom reactor. From Reference 1. Reproduced by permission.

A detailed drawing of a simple metal atom reactor, largely build from commercially available parts, is given in Fig. 2. The main reaction chamber consists of a 3000-mL reaction flask and a four-necked top section. This reactor is suitable for all the experiments described in this chapter, with the possible exception of the molybdenum compounds. For syntheses of a practical scale with refractory metals (vaporization temperature greater than 2000°, e.g. Re, Mo, and W) a larger diameter reactor (140-178 mm) with a standard wall thickness (about 3.5 mm) is recommended to improve heat dissipation. 

The maximum pressure that should be tolerated in a metal atom reactor is a point of controversy among various workers in this field. High pressures favor reaction in the gas phase with respect to those in the matrix. Where different products are obtained from the gas and condensed phases, the former products begin to appear at pressures of 10 4 torr. The molybdenum atom syntheses described in this volume are best carried out under 10 4 torr and with apparatus described in synthesis number 16. Skell and co-workers consider this apparatus necessary and appropriate for all work. 

A Teflon-coated magnetic stirring bar is placed in the reactor flask, and the metal atom reactor is assembled and pumped down to less than IX 10 3 torr as described in Section 11. Thirty milliliters (20 mmole) of l,3-bis(trifluoromethyl)-... 

Fig. 1. Detail of reaction zone of the metal-atom reactor. Suitable reactor dimensions are 15-18 cm diameter, 5 mm wall thickness and 36-46 cm depth. The water-cooled electrodes are 7.5 cm apart. The central substrate inlet tube, a 6 mm od Pyrex slightly constricted at the end, extends 5 cm below the liquid nitrogen level. A 14 mm od Pyrex tube which serves as a substrate deflector is positioned 5 cm below the inlet nozzle and is suspended horizontally between the electrodes. A built-in Pyrex syphon tube extends to the bottom of the reactor for the removal of air sensitive products under an inert atmosphere.

A solar panel, a windmill, an atomic reactor, a dam on a river, and a steam turbine are all examples of methods that could be used to create... 

Cobalt-60 is made by exposing ordinary inexpensive cobalt in an atomic reactor. Strontium-90 is a fission product in nuclear power plants and has a higher beta radiation than cobalt-60. Cesium-137 is a fission product found in all nuclear reactors and must be removed from time to time to maintain efficiency. Evidently large quantities of strontium-90 and cesium-137 will be available in the year to come. 

The minor and trace elements in coals are currently determined by several techniques, the most popular of which are optical emission and atomic absorption spectroscopy. Neutron activation analysis is also an excellent technique for determining many elements, but it requires a neutron source, usually an atomic reactor. In addition, x-ray fluorescence spectroscopy, electron spectroscopy for chemical analyses (ESCA), and spark source mass spectroscopy have been successfully applied to the analyses of some minor and trace elements in coal. 

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